Device for effectively quenching the arc



Jan. 19, 1937. A. LOTZ DEVICE FOR EFFECTIVELY QUENCHING THE ARC FiledMay 1935 Patented Jan. 19, 1937 UNITED- s'mi'rss- POATENT" OFFICE DEVICEFOR EFFECTIVELYQUENCHING THE ARC Application May 24, 1933, Serial No.872,670

' In Germany May 24, 1932 13 Claims. (Cl. 200148) The invention relatesto devices for effectively quenching the electric arcs which result fromthe separation of the contacts in switches or the melting of fusiblecutouts and the like in alternating current circuits.

-There exist switches in which the arc is subjected to a powerful blastof compressed air or other gas during the time the current value iszero, and by this means a restoration of the arc with returning voltageis prevented. The blast of compressed air or other gas causes alengthening of the arc and at the same time removes the ionized currentcarriers from the space between the electrodes.

In another type of switch two tubular e1ectrodes disposed within apressure chamber are provided. When the electrodes separate the gas orliquid contained within the surrounding pressure chamber flows throughthe centrally disposed openings in the electrodes and thereby causes thearc to be-lengthened and the ends of the are to be moved within thehollow electrodes.

The present invention distinguishes from these previously knownarrangements wherein a stream of air or other gas under very highpressure is used to lengthen the are both in structure and method ofoperation, The are is estab-, lished within a tubular passage formed ina suitable member of insulating material. The dimensions of the arcpassage are such that the arc is closelvconflned by the adjacent walls,and the stream of arc extinguishing gas is admitted under moderatepressure, at right angles to the axis of the are passage. This stream ofgas tends to press the are against the opposite wall of the arc passage.Movement of the arc in this direction is, however, definitelylimited,due to the presence of the confining walls of the arc passage, and inaddition, ,it is impossible, because of the proportioning of the arcpassage, for the out-flowing stream of gas to bow out the are as is donein the prior art structures. By this arrangement, any substantiallengthening of the arc is prevented, and in addition, the arc is held ina position where the outfiowing stream of gas can most effectivelyproduce the desired extinc tion. In the accompanying drawing I haveillus trated several embodiments of my preferred invention. I n

. Figure 1 shows the invention as applied to a fusible cutout. The fusewire ,1" is clamped be-- tween electrodes a and b and extends through atubular opening 02 formed within-an insulating body 0. When the wire ,ffuses, due to overload,

an arc is established in the opening or are pas- Q sage d. Perpendiculartopassage d, is a channel e which passes through the insulating body 0,and through this channel, the momentan arc is formed, a gas such as air,carbon dioxide, or

the like is blown. The dimensions of the arc passage d within theinsulating body c are such that the arc is forced against the oppositewall in the passage d and, by virtue of the confining action of thatwall, is prevented from lengthening.

The resulting intimate co-mingling of the arc and the fresh un-ionizedgas which is forced into the arc passage through the channel e effectsthe extinguishment of the arc at the first zero point in the currentwave. The fresh un-ionized gas blown into the arc passagevents througheither Figs. 2 and 3 show a switch according to my invention in theclosed and opened positions,

respectively. The moving contact a is adapted fixed contact d. The crosssectional dimensions of the are passage d and the moving contact a aresuch that the conduit passage e utilized for introducing the arcextinguishing gas into the arc passage is substantially closed when thecircuitis in the closed circuit position.

During the circuit opening operation the moving contact a is moved fromthe position shown in Fig. 2 to the position shown in Fig. 3. Thismovement draws an arc longitudinally ,within the arc passage d and atthe same time allows a quantityof an arc extinguishing gas to be forcedinto the arc passage through the conduit opening e. The confining actionof the arc passage it prevents the resulting stream of gas flowingtherein from bowing out and thereby lengthening the arc, and sincethepassage is open at either end when the switch is in the open circuitposition, the fresh un-ionized gas flowing through the arc passageeffectively removes all of the current carrying bodies so as to preventthe restriking of the arc.

Figs. 4,8 and 6 show a switch wherein the cross sectional area of thearc passage maybe varied according to the physical dimensions of the areshown in Figs. 1 and 2. The are passage d wherein the moving contact itmoves is defined by a pair or substantially parallel wall members 0 andis adapted to be closed at the lower end by a rectangular member Ihaving a conduit opening e therein. The upper surface oi! the arcpassage d is defined by a movable slider member h of insulating materialwhich is biased toward the member 1 by means of a pair of suitablesprings 1'.

When the switch is in the closed circuit position the slider member Itbears against the upper surface of the rectangular moving contact a. Assoon as the moving contact a disengages the arc passage d during thecircuit opening operation, the slider it moves downwardly under theinfluence of its biasing springs so as to restrict the cross sectionalarea of the arc passage. The

amount or this restricting depends upon the physical dimensions or thearc, which is to say that it depends upon the magnitude oi the arccurrent, since one is a function of the other. By this arrangement aclose confinement or the are within the arc passage dis assured, and thearc is prevented from bowing out and moving away from the in-comingstream of arc extinguishing gas which flows through the conduit e atright angles to the longitudinal axis of the arc passage. As a result,the arc is prevented from being lengthened by the in-flowing stream ofgas. and a rapid extinguishment thereof is effected.

The length of the arc passage d, which is determined by the dimensionsof the insulating body 0, depends upon the voltage and thecharacteristics of the circuit with which the switch is to be used. I!this voltage is very high, it is possible to arrange a plurality ofdevices such as that shown in Figs. 4, 5, and 6 in such manner that thearc passages d in the several units shall aline one with the other. IIthis is done, the interruption of the arc is greatly facilitated, due tothe fact that individual sections thereoi are each subjected to aseparate stream of gas which enters the arc passage 01. each of theseveral devices substantially at right angles to the longitudinal axisthereof. In other words each device acts to eflect the extingulshment ofa section of the arc. It is, or course, necessary that the insulaingbody c be so dimensioned that flash-over will not occur due to thepresence of ionized gas or abnormal circuit voltage.

The are passage d within the insulating body c may be of any crosssection, and the body c'may be 'formed of any suitable material, itbeing important merely that the material is insulating. Porcelain,molded material, fibre impregnated with artificial resin (hard paper,linen), alumina or steatite have all been used'with satisfactoryresults. 1: metal is used in any portion of the wall defining body 0',it is necessary that the surface thereof which is exposed to the arcshall be provided with a layer oi insulating material capable ofwithstanding the normal circuit voltage. It is possible to use wood(particularlyoak or beech) or oil impregnated wood for definingthewallsotthearce.

In the two structures illustrated there is only one conduit or channel ethrough which the arc extinguishing gas is introduced into the 'arcpassage. It may be desirable to provide an annular space disposed aroundthe arc passage d which is provided with a number of radially directedborings connected with" the arc passage. If this is done, the arcextinguishing gas may be caused to flow into the arc passage at aplurality of similar to the contacts a and b of. the switch points andthe operation will thereby be somewhat improved.

For cooling purposes, the arc passage wherein the arc is formed may besurrounded by a water jacket, the simplest means of accomplishing thisbeing the provision or an annular passage within the walls oi! aninsulating body, and ii desired, small channels may be provided leadingfrom this space into the arc passage itself in such manner that thecooling water may percolate down through these channels so as to coverthe internal, surface of the arc passage with a film of water.

Fig. Tillustrates schematically one method of connecting a circuitinterrupter according to my invention into an electrical circuit. Asshown, the moving contact a of the breaker which is electricallyconnected to one side or the power circuit, is adapted to move within asuitable guide means a, and is biased to the open circuit position by aspring h associated with the breaker operating solenoid k. A gasreservoir is provided for producing the blast of arc extinguishing gasthrough the arc passage :1 within the insulating body 0, and theliberation of this gas is controlled by an electromagnetic valve. Anoverload relay electrically connected in the power circuit is providedfor controlling the operation of the switch and the electromagneticvalve. The breaker operating solenoid k is normally energized in orderto hold the contacts in the closed circuit position.

Upon the occurrence of an overload, the over load relay moves todeenergize the electromagnetic valve and the breaker operating solenoidI: thereby making it possible for the biasing spring h to move thecontacts to the open circuit position.

At the same time the electromagnetic valve operated tocause a definitequantity or the gas contained within the gasreservoir to flow throughthe arc passage, thereby eii'ecting the extinguishment of the are whichis drawn therein.

It will thus be seen that I have provided an improved circuitinterrupter wherein the are which is established incident to the openingof the connected circuit is extinguished through the agency 01' aflowing stream of un-ionized gas. The structure of my invention difiersfrom the devices already known to the art in that the arc is so confinedthat the stream of arc extinguishing gas does not effect a substantiallengthening of the arc, but intimately co-mingles with the arc andthereby operates much more eiiiciently in effecting the extinguishmentthereof.

I claim as my invention:

1. In a circuit interrupter, means at least partially of insulatingmaterial for defining the walls or an arc passage having a length whichis at least several times its greatest cross sectional dimension, meansfor establishing an are within said are passage, and means including aconduit which opens into said arc passage intermediate itsends forcausing a quantity of arc extinguishing fluid to flow through said arcpassage during each circuit interrupting operation in order to eflfectthe extinguishment of said arc, said are passage being open at least atone end when said interrupter is in the open circuit position, and atleast a portion oi said wall defining means comprising a member ofinsulating material which is movable to vary the cross sectional area ofsaid are passage during the circuit opening operation so as to preventsaid quantity of fluid from bowing said arc.

2. In a circuit interrupter, means at least partially of insulatingmaterial for defining the walls of an arc passage having a length whichis at least several times its greatest cross sectional dimension, meansfor establishing an arc within said are passage, and means including aconduit which opens into said arc passage intermediate its ends forcausing a quantity of arc extinguishing fluid to flow through said arepassage during each circuit interrupting operation in order to effectthe extinguishment of said are, said are passage being open at both endswhen said interrupter is in the open circuit position and, except forsaid conduit, being otherwise closed, said fluid being introduced intosaid passage under pressure and ata substantial angle to thelongitudinal axis thereof, and at least a portion of said wall definingmeans comprising a member of insulating material which is movable tovary the cross sectional area of said are passage in response to thephysical dimensions of the are which is established therein during thecircuit opening operation, thereby preventing said quantity of fluidfrom bowing or otherwise lengthening said are. 3. In a circuitinterrupter, means at least partially of insulating material fordefining the walls of an arc passage having a length which is at leastseveral times its greatest cross sectional dimension, means forestablishing an are within said arc passage, means including a conduitwhich opens into said are passage intermediate its ends for causing aquantity of arc extinguishing fluid to flow through said are passageduring each circuit interrupting operation in order to eflect theextinguishment of said are, said are passage being open at least at oneend when said interrupter is in the open circuit position, and means forvarying the cross sectional area of saidare passage in response to thephysical dimensions of the are which is established therein during thevcircuit opening operation, thereby preventing said quantity of fluidfrom bowing or otherwise lengthening said arc, said area varying meanscompris-v ing a member movable into said are passage during theoperation of said interrupter and means for moving said member in suchmanner that the cross sectional area of said are passage shall beproportional to the physical dimension of the arc which is establishedtherein.

4. In a circuit interrupter, a pair oi oppositely disposed, spacedplates formed at least partially of insulating material and each ofwhich has a considerable surface area, for defining two of the walls ofan arc passage, means for establishing the arc incident to each openingoperation of said interrupter within said are passage, and means fordefining the other walls of said are passage, including a memberslidable edgewise in the plane of said arc between said pair of opposedplate members to cause the dimensions of said are passage to be variedin response to the current magnitude of the are which is establishedtherein during the operation of the said interrupter. I v

5. In a circuit interrupter, a pair of substantially flat plates ofinsulating material, positioned in parallel planes and spaced somedistance from each other, for defining two of the opposed walls of arectangular arc passage, means of insulating material for defining theother two walls oi. said arc passage in order that said passage shall besage including a flat member of insulating material slidable edgewise inthe plane of said are between said opposed plate members to vary thedimensions of said are passage in accordance with the current magnitudeof the are which is established therein, and means for resilientlybiasing said slidable member to a position where the cross sectionalarea of said are passageis reduced to a predetermined minimum.

6. In a circuit interrupter, a pair of substantially flat plates ofinsulating material, disposed,

in parallel planes and spaced some distance from each other, fordefining two of the opposed walls lishing the arc incident to eachopening operation of said interrupter within said are passage, saidmeans for'defining the other two walls of said are passage including amember of insulating material slidable. between said opposed plates tovary the dimensions of said arc passage in accordance with the currentmagnitude of .the are which is established therein, and means, includinga con-' duit which opens into said arc passage intermediate the endsthereof, for causing a. quantity of arc extinguishing fluid to flowthrough said arc passage during each circuit interrupting operation,said slidable member causing the physical dimensions of said are passageto closely approximate the physical dimensions of said are at all times,thereby effecting intimate contact between said are extinguishing fluidand the arc.

7. In a circuit interrupter, means, at least partially of insulatingmaterial, for defining the walls of an arc passage having a length whichis at least several times its greatest cross section dimension, meansfor establishing the arc incident to each opening operation of saidinterrupter within said are passage, means including a conduit whichopens into said are passage intermediate its ends, for causing aquantity of arc extinguishing fluid to flow through said are passageduring each circuit opening operation in order to effect theextinguishment of said arc, and means for varying the cross sectionalarea of said are passage in response to the physical dimensions of thearc which is established therein during the operation of saidinterrupter, in order to assure intimate contact between said areextinguishing fluid and said arc.

8. In a circuit interrupter, means, at least partially of insulatingmaterial, for defining the walls of an arc passage having a length whichis at least several times its greatest cross sectional dimension, meansfor establishing the arc incident to the opening of said interrupterlongitudinally within said are passage, and'iiieans, including a conduitwhich opens into said are passage intermediate its ends-for causing aquantity of arc extinguishing fluid to flow through said are passageduring each circuit interrupting operation in order to efi'ect theextinguishment of said arc, said are passage being open at least at oneend when said interrupter is in the open circuit position and except forsaid conduit being otherwise substantially completely enclosed, saidwell defining means including a member of insulating material which ismovable'to vary the cross sectional area of said are passage in responseto the physical dimensions of the are which is established thereinduring the operation of said interrupter, thereby assuring intimatecontact between said are extinguishing fluid and said are.

9. In a circuit interrupter, means at least partially of insulatingmaterial for defining the walls of an arc passage having a length whichis at least several times its greatest cross sectional dimension, meansfor establishing the arc incident to the opening of said interrupterlongitudinally within said are passage, means, including a con duitwhich opens into said are passage. intermediate its ends, for causing aquantity of arc extinguishing fluid to flow through said are passageduring each circuit interrupting operation, in' order to effect theextinguishment of said are, said are passage being open at both endswhen said interrupter is in the open circuit position and except forsaid conduit means being otherwise substantially completely enclosed,said fluid being introduced into said passage under pressure, and atleast a portion of said wall defining means comprising a resilientlybiased member of insulating material which is movable to vary the crosssectional area of said are passage in response to the physicaldimensions of the are which is established therein during the operationof said interrupter.

10. In a circuit interrupter, means at least partially of insulatingmaterial for defining the walls of an arc passage, means forestablishing the .arc incident to each opening operation of saidintcrrupter within said are passage, a source of arc extinguishing fluidexternal to the arc passage, means for causing a blast of said areextinguishing fluid to be moved into and to flow through said arepassage longitudinally thereof to effect the cxtinguishment of saidarc,'said arc passage being open at least at one end thereof during eacharc extinguishing operation and being otherwise substantially completelyenclosed, and movable means of insulating material for varying the crosssectional area of said are passage intermediate said are establishingmeans in response to the physical dimensions of the arc which isestablished therein during the operation of said interrupter in order toassure intimate contact between said are extinguishing fluid and saidarc.

11. In a circuit interrupter, means at least partially of insulatingmaterial for defining the walls of an arc passage having a length whichis at least several times its greatest cross sectional dimension, meansfor establishing the arc incident to each opening operation of saidinterrupter within said are passage, a body of arc extinguishing fluid,means including a conduit which opens into said are passage intermediateits ends for causing a quantity of said are extinguishing fluid to bemoved into and to flow through said are passage during each circuitopening operation to elect the extinguishrnent of said are, said'arcpassage being open at least at one of its ends during each arcextinguishing operation and except for said conduit being otherwisesubstantially com- 2,oes,422

pletely enclosed, said are extinguishing fluid being introduced intosaid are passage under pressure and at a substantial angle to thelongitudinal axis thereof, and meansfor varying the cross sectional areaof said are passage in response to the physical dimensions of the arewhich is established therein during the operation of said interrupter inorder to assure intimatecontact between said are extinguishing fluid andsaid are.

12. In a circuit interrupter, means at least partially of insulatingmaterial for defining the walls of an arc passage having a length whichis at least several times its greatest cross sectional dimensions, meansfor establishing the arc incident to each opening operation of saidinterrupter longitudinally within said are passage, a body of arcextinguishing fluid, and means including a conduit which opens into saidare passage intermediate its ends for causing a quantity of said areextinguishing fluid to flow through said arc passage duringeach circuitinterrupting operation in order to effect the extinguishment of saidarc,

said are passage being open at least at one end during each arcextinguishing operation and ex cept for said conduit means beingotherwise sub stantially completely enclosed, said fluid beingintroduced into said are passage under pressure and at a substantialangle to the longitudinal axis thereof, and at least a portion of saidwall delining means comprising a resilient biased member of insulatingmaterial which is movable to vary the cross sectional area of said arepassage in response to the physical dimensions of the are which isestablished therein during the operation of said interrupter.

13. In a circuit interrupter, a pair of substantially flat plates ofinsulating material disposed in parallel planes and spaced some distancefrom each other for defining two of the opposed walls of an arc passagehaving the general form of a rectangular prism, means for establishingthe arc incident to each opening operation of said interrupter withinsaid are passage, means for defining the other two walls of said arcpassage including a member of insulating material slidable between saidopposed plates to vary the dimensions of said arc passage in accordancewith the physical dimensions of the are which is established therein,and means for causing a blast of arc extinguishing fluid to flow throughsaid are passage during each circuit interrupting operation

